Experienced marksmen need to account for bullet drop and windage over different temperature ranges and altitudes when aiming at a target. Precision long range shooters, such as military or police marksmen, often rely on pre-computed ballistic data cards to get the correct compensation factors to compensate for bullet drop and windage. In the field, the ballistic data cards may be attached to an arm band that is worn on the shooter's arm. A problem with this approach is that the ballistic data card attached to an arm band is usually not visible to the shooter while looking through a scope and taking aim at a target. If the shooter refocuses even momentarily on a ballistic data card that is attached to an arm band, the target may no longer be in sight when the shooter's attention is turned back to the target.
Accordingly, there is a need for a device that is capable of displaying ballistic data to a shooter that is within the field of view of the shooter while the shooter is taking aim at a target.